He added that Apple is far ahead of its expectations on available apps for the watch. The iPhone launched with about 500 available apps and the iPad launched with roughly 1,000. The internal goal for Apple Watch was to beat that 1,000 level, but the device instead hit over 3,500 apps, Cook said.

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"We couldn't be happier about how things are going from that point of view," he said.

The Apple Watch, which requires an iPhone 5 or later to run basic apps and receive notifications, is Apple's first new device since the iPad launched five years ago and the first new product category under the leadership of Cook. The device is key for Apple to show it's still an innovator and can expand beyond its wildly successful iPhone franchise, which makes up the bulk of sales and profits.

So far, Apple Watch has been experiencing long shipping delays. Wait times for the device, which costs from $349 for the sport version to $17,000 for the gold edition, now stretch into July.

Despite those delays, Cook said he believes Apple will be prepared to expand to new countries in about two months. He added that because of all the different watches and bands available -- with far more choices than with most Apple products -- the company has had to make adjustments to align with demand.

"But I'm really confident this is something we really understand how to do and will do," Cook said. "So I'm really happy where we are currently."